core

## Constructing a Plane Feature

Construct Plane dialog box

There are several methods to use PC-DMIS to construct a plane. The following table lists the various types of constructed planes along with their necessary inputs. Some features may require no inputs, while others may require three or more inputs. In the following table, the term "Any" indicates that the construction can take any type of feature as input for construction. PC-DMIS allows the features to be selected in any order.

CONSTRUCT FEATURE TYPE | SYMBOL IN EDIT WINDOW | # OF INPUT FEATS | FEAT #1: | FEAT #2: | FEAT #3: | COMMENTS
Auto Plane | - | - | - | - | - | See "Auto Plane Construction".
Alignment Plane | ALIGN | 0 | - | - | - | Constructs a plane at alignment origin.
Best Fit Plane | BF | At least three inputs are needed. | - | - | - | Constructs best fit plane using the given inputs. See the Note below for recommended inputs.
Best Fit with Recomp Plane | BFRE | At least three inputs are needed (one must be a point). | - | - | - | Constructs a best fit plane using the given inputs. See the Note below for recommended inputs.
Cast Plane | CAST | 1 | Any | - | - | Constructs a plane at the centroid of the input feature.
Primary Datum Plane | PRIMARY DATUM | 3 or 1 | Any (one of three) Or if only one input: one feature set, one plane, or one scan | Any (2 of 3) | (Any 3 of 3) | Constructs a plane tangent to the highest available points.
Mid Plane | MID | 2 | Any | Any | - | Constructs a mid plane between the centroids of the inputs.
Offset Plane | OFFSET | 3 or 1 | Any (one of three) Or plane feature if only one input | Any (2 of 3) | Any (3 of 3) | Constructs a plane offset from the input features (or from single plane feature).
Parallel Plane | PLTO | 2 | Any | Any | - | Constructs a plane parallel to the first feature and passing through the second feature.
Perpendicular Plane | PRTO | 2 | Line or Axis Element | Any | - | Constructs a plane perpendicular to the first feature and passing through the second feature.
Reverse Plane | REV | 1 | Plane | - | - | Constructs a plane passing through the input with a reversed vector.
Translated Plane | TRANSLATED | 1 | Plane with point data | - | - | Constructs a plane at an offset from the input plane.

For Best Fit (BF) or Best Fit Recompensate (BFRE) constructions, while you can use any feature type for your input features, BF and BFRE fit types are typically used with point features or point sets (a scan of points, a feature set with points, or an expression that resolves to an array of points).

To construct a plane:

1. Open the Construct Plane dialog box (Insert | Feature | Constructed | Plane).

2. From the list on the right, select the desired input features.

3. From the drop-down list on the left, select the method of construction. Available options include:

- Auto Plane

- Alignment Plane

- Best Fit or Best Fit Recompensate Plane

- Cast Plane

- Mid Plane

- Perpendicular Plane

- Parallel Plane

- Reverse Plane

- Primary Datum Plane

- Offset Plane

- Translated Plane

4. Click the Create button.

The Edit window command line for a sample plane construction would read:

feature_name=FEAT/PLANE,TOG

THEO/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec

ACTL/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec

CONSTR/TOG2,TOG3,......

If TOG2 = PLANE and TOG3 = BF or BFRE, the command has the following format:

feature_name=FEAT/PLANE,TOG1,TOG6

THEO/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec

ACTL/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec

CONSTR/PLANE,TOG3

OUTLIER_REMOVAL/TOG5,stdDevMultiplier

FILTER/TOG5,WAVELENGTH= cutoffWavelength

The actual Edit report displays in all capital letters.

AUTO is the default method of construction. This option automatically determines the best way to construct a plane using the input feature(s). See "Auto Plane Construction".

TOG1= POLR or CARTESIAN

TOG2 = PLANE

TOG3 = ALIGN / BF / BFRE / CAST / TANGENT / MID / OFFSET / PLTO / PROJ / PRTO / REV / TRANSLATED

TOG5 = ON / OFF

TOG6 = LEAST_SQR / MIN_SEP

stdDevMultiplier = This multiplier value determines whether or not a measured point is an outlier. If the point from the plane is further than the standard deviation multiplied by this, then it is an outlier and will be removed if you have selected the Remove Outlier option.

cutoffWavelength = This value controls the amount of data smoothing. The longer the wavelength the more smoothing there is.

The first three lines that display in the Edit window are the same for constructed planes. The fourth line is slightly different, according to the type of feature being constructed. To switch between the different types of planes, place the cursor on TOG3 and press F7 or F8. (See "Command Mode Keyboard Functions" in the "Using the Edit Window" chapter.)

When two or more features are involved, PC-DMIS automatically determines the necessary order of the input features. This improves the accuracy of the measurement process.

The following subtopics describe the available options for constructing a plane:

More:

Using the Display Area

Auto Plane Construction

Constructing a Plane from an Alignment

Constructing a Best Fit or Best Fit Recompensate Plane

Constructing a Cast Plane

Constructing a Mid Plane

Constructing a Perpendicular Plane

Constructing a Parallel Plane

Changing the Direction of a Plane

Constructing a Primary Datum Plane

Constructing an Offset Plane

Constructing a Translated Plane

Exporting Plane Features in IGES